Telephone apparatus.



l PATENTED JULY- 30, 1907.

C. S.-WINSTON. TELEPHONE APPARATUS.

APPLICATION nun JAN. 3, 1905.

w m/w UNITED STATES PATENT orrron.

CHARLES S. WINSTON, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGGSWlTCHBOARD & SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OFILLINOIS.

TELEPHONE APPARATUS.

Specification of Letters Patent.

Patented July 30, 1907.

Application filed nuary 3, 1905. Serial No. 239,371.

To all whom it may concern:

Be it known that I, CHARLns S. WINSTON, a citizen of the United States,residing in Chicago, county of Cook, and State of Illinois, haveinvented certain new and useful Improvements in Telephone Apparatus, ofwhich the following is a specification.

My invention relates to improi/ements in telephone apparatus andparticularly to means for preventing the extra current or kick of amagnet coil from affecting other apparatus in the circuit of the coil.It is well known that when a current flowing through a magnet coil isvaried the turns of the coil react upon another inductively to producewhat is known as the extra current or kick. This current is found inpractice to interfere more or less with the proper operation of otherapparatus in the same or related circuits, and my invent.on is designedto-prevent such interference. In carrying out the invention I prefer toplace a non-inductive resistance in parallel with the coil thussubjected to varying current by means of which the currents induced bythe said coil are short circuited and do not flow in the remainder ofthe circuit to affect other apparatus that may belocated therein. 1 havefound this arrangement of value in connection with circuits wherein arelay provided with a locking winding is initially operated byalternating current through its main winding and where the circuit ofsaid locking winding contains the magnet of a signaling or other device.In such cases, the current in the main coil induces a correspondingcurrent in the locking coil, which current iiows through said magnetcoil in the locking circuit and the kick or extra current from thelatter caused by such induced current flows back through the lockingwind ing and deenergizes said relay and opens its locking circuit, thusdefeating the object of the locking circuit. By placing such anon-inductive resistance around the magnet in the locking circuit,however, all trouble is avoided since such extra currents do not thenpass through the said locking winding but are confined locally to thecoil and resistance.

The invention includes still other improvements in circuit arrangementsall of which will be pointed out in the detailed description and claimsin connection with the accompanying drawing forming part of thisspecification in which the same reference characters are used throughoutto designate like parts, and in which:

Figure l is a diagram of a telephone trunk or transfer circuit embodyingone form of the improvements, and Fig. 2 is a similar view of adifferent trunk circuit showing another application of a part of myimprovements.

Referring to Fig. A indicates a trunk or transfer circuit extendingbetween two central offices or switclr board sections; C, a cord circuitof which only the call ing end is shown, and D another cord circuit ofwhich only the answering end isshown. These cords are adapted to beconnected with the two ends of the trunk for the ordinary purposes ofestablishing connections for conversation thereover.

A relay 1' is located at the D end of the trunk and is provided with amain or actuating winding 2 bridged between the main conductors of thetrunk and with a locking winding 3, one terminal of which is joined byconductor 4 with one of the normally closed contacts 5 of the jack .T ofthe trunk, the other of which contacts is grounded. The second terminalof thev said locking winding is connected to the forward contact of thespring of said relay r, and the spring is united by wire 6 with one endof the winding of a signal controlling relay r whose other terminal, isjoined directly to the live pole of the battery B. The relay 1' controlsthrough its normally open contacts the local circuit of the signal Sassociated with the corresponding end of the trunk,

The operation of the apparatus so far described is as follows: Assumingthe connection for conversation to have been initiated at the left, theinsertion of the plug of-the cord circuit C into the jack of the trunkand the.

immediate depression or operation of the ringing key causes current'fromthe alternating ringing generator '7 to flow over the trunk and throughthe actuating winding of relay r thereby energizing the said relay andcausing it to close the circuit through the relay r to in turn close thecircuit of and operate lamp S to attract the attention of the operatorat the section D. This circuit of relay 1' also includes the lockingwinding 3 of relay 1" which is intended to maintain said relay energizedeven after the ringing current is cut off from generator 7 to cause thecontinued operation of signal S until the operator notices the same andanswers by inserting the plug of her cord circuit and connecting herhead telephone 8 therewith, the insertion of the said plug openingcontacts 5 of jack J to thereby dener-.

gize both relays r and r It is found in practice, however, that the saidlocking circuit does not remain closed for the reason that the varyingringing current through coil 2 of relay 1" induces a similar current inthe said locking winding, and such changing current through relay 1'causes a kick or an extra current there- .from to flow in said lockingcircuit and when of therelay 1 of Fig. 1.

cuited and do not flow through the locking winding of relay r. Thewindings of relay r may have 500 ohms each, the relay 1 500 OhIIISICSlSlZZLIICG 9, 200 ohms, and the battery 24 volts. Under theseconditions the said relay 1 is nottripped by the kick oi r and thesystem operates in the intended manner as above described.

In Fig. 2, the invention is shown applied to a different arrangement ofcircuits. The connection of the cord circuit at the left with the trunkjack and the immediate operationof the ringing key causes current fromthe ringing generator to flow over the trunk and through the mainwinding of relay 1 corresponding to The attraction of its.springcompletes a circuit from battery B over conductor 10, through thewinding of the mechanical signal 1]. corresponding to relay r of Fig. 1,and thence through the locking winding of relay 1' conductor 12 and thenormal contact of relay r to ground. The current in this path keeps thesignal 11 and relay 1 energized, and to pre= vent the opening of thislocking circuit due to the inductive surge of current from the coil ofsignal 11 caused by the ringing current, the non-inductive resistance 9is connected in parallel with said signal 11 to thereby short circuitthe said surges of current. Now, when the operator listens in andobtains the order and inserts the plug of the trunk in the jack of theline L, the said locking winding of relay 1' is short circuited throughthe third strand 13 of the trunk cord and the grounded ring 14 of theline jack, thus permitting the spring of relay'r to drop back and engageits normal contact which is connected by conductor 15 with the forwardcontact of relay 1". The subscriber on line L is called in the usual wayand when he responds current from the battery 13 in the cord circuitflo'ws over the complete metallic circuit formed by the trunk and lineand operates relay r thereby again energizing signal 11 which shows tothe incoming operator that the called subscriber has responded.

At the termination of the conversation the return or" the subscriberstelephone deenergizes the relay 1" as well as the tip cord circuitsupervisory relay to thus light the cord circuit supervisory lamp and toretire the mechanical signal 11. Thus both operators are informed of theend of the conversation, and the plugs are taken down and all partsrestored to normal condition.

A call coming in over line L is answered by inserting the trunk plug inthe jack, thereby permitting current from battery B which is the same asbattery B to flow over the metallic line and through the line signalingrelay r", to call the operator at the other oflice, who may attend tothe connection in the usual manner.

In the above described circuit it will be observed that the relay r isrendered inoperative by short circuitiug its winding over the thirdstrand of the cord instead of the more common method of utilizing anadditional relay or other complicated arrangements.

While I have thus described my improvements with special reference tothe details of certain forms that have been found satisfactory forcommercial purposes, I do not wish to be limited thereto in all respectsas it is obvious that various changes and alterations may be madetherein without departing from the scope and principle of the same.

But having thus described the invention what I desire to secure byLetters Patent is:

1. The combination, with an electromagnet in a circuit subjected tovarying currents, of other apparatus in the circuit of saidelectro-magnet, a non-inductive resistance permanently connected inparallel with said magnet to prevent the kick or extra current from themagnet coil from affecting said other apparatus, substantially asdescribed. v

2. The combination, with a relay having an actuating and a lockingwinding of a source of varying current adapted to send current throughsaid actuating winding to initially operate said relay, an electromagnetand a sou1'ce of steady current in the circuit of said locking winding,and a non-inductive resistance connected around the coil of said magnetwhereby the extra current from the latter caused by the varying currentin its circuit in duced by the two windings of said relay is shortcircuited and the locking relay is not prevented from looking,substantially as described.

3. The combination with an electro-magnet having an actuating coil,- ofmechanism affected by the energization of said magnet, a source ofdirect current in series with said coil, means also in the circuit ofsaid coil for varying the current through the coil, and a non-inductiveresistance in parallel with the coil whereby the selfinduced currentfrom the coil will be shunted away from other parts of the circuit,substantially as described.

4. The combination with a telephone trunk circuit, of a relay associatedwith said circuit adapted to be actuated by varying current in saidcircuit, a locking winding for said relay, an eleetro-magnet adapted tobe actuated in series with said locking winding, mechanism affected bysaid eleetro-Inagnet, a non-inductive resistance in parallel with saidelectro-magnet whereby the selfinduction of said coil will not sendcurrent through said locking winding in opposition to the lockingcurrent, substantially as de scribed.

5. The combination with a trunk circuit, of a relay associated therewithand adapted to be actuated by varying current in said circuit, a lockingwinding for said relay adapted to be energized by current from a steadysource, an electro-magnet adapted to be placed in series with saidlocking winding, mechanismaifected by the energization of saidelectro-magnet, and means associated with said electro-magnet wherebythe self-induction of its coil will not send current through saidlocking winding in opposition to the current from said steady source,substantially as described.

6. In a telephone system, the combination with a trunk in said line, alocking winding for said relay adapted to be energized by steadycurrent, an electro-magnetie device adapted to be placed in series withsaid locking winding, mechanism affected by the energization of saidelectromagnetic device, and means whereby the self-inductive etfectproduced in said electro-magnetie device by the varying current inducedin said locking winding will be shortcircuited through a path which doesnot include said locking winding, substantially as described.

7. In a telephone system, the combination with a trunk line extendingbetween difierent switchboard sections and terminating at its outgoingend in a jack and at its incoming end of a cord and plug, of a cordcircuit adapted to connect with the outgoing end of said trunk, and atelephone line with which the incoming end is adapted to be connected, arelay associated with the incoming end of ,said trunk adapted to beactuated by varying current in 8. In a telephone system, the combinationwith a trunk line extending between difierent switchboard sections andterminating at its outgoing end in a jack and at its inc0n1- ing end ina cord and plug, of a cord circuit adapted to connect with the outgoingend of said trunk, and a telephone line with which the incoming end isadapted to be connected, a relay associated with the incoming end ofsaid trunk adapted to be actuated by varying current in the trunk, alocking winding for said relay, a magnetic signal adapted to be actuatedin series with said locking winding, a non-inductive shunt for saidsignal adapted to short-circuit the self-induced current from its coilaway from said locking winding, means associated with the plug for saidtrunk line whereby said locking winding is shortcircuited by theinsertion of the plug in the jack of said telephone line and saidmagnetic signal is eftaced, and a relay adapted to be actuated bycurrent over the trunk when the called subscriber answers, his call toagain actuate said magnetic signal over a path which does not in cludesaid locking winding, substantially as described.

9. In a telephone system, the combination with a connecting circuit, ofa relay associated therewith and adapted to be actuated by varyingcurrent, a locking circuit for said relay, an electro-magnetic device inseries with said locking circuit, and a source of direct current toenergize said locking circuit, a non-inductive shunt about saidelectro-magnetic device adapted to receive the self-induced currentsfrom the device and thereby shunt such currents away from the coil ofthe relay, whereby the locking circuit becomes effective, substantiallyas described.

Signed by me at Chicago, county of Cook and State of Illinois in thepresence of two witnesses.

CHARLES S. WINSTON.

Witnesses:

ROBERT LEWIS AMES, EDITH F. Gama.

